Re: Of Martian Sculptures (was: Re: [asa] on science and meta-science)

Iain, you wrote:

>Sorry, but I'm not convinced. I think you do have independent knowledge of
>the likely nature and inclinations of the designer of the spacecraft.

Of the WHAT of the spacecraft? Introducing the word "designer" at this
point in the argument is illegitimate. The starting point of the
"spacecraft" scenario is that *we have not yet decided whether the
spacecraft is a designed object, or some accidental conglomeration of matter
that merely looks designed*. Similarly, the starting point of my Martian
sculpture scenario is that we have not yet decided whether the sculptures
were designed, or formed by accidental and natural processes (such as
erosion, earthquakes, or meteor strikes). If you did not understand my
examples in this way, then we are talking at cross purposes. Did you
suppose that I was asking the question whether the designer of the
sculptures and the spacecraft was God, as opposed to aliens? I was not. I
was asking whether or not we could tell, without knowing anything about a
putative designer, that both the spacecraft and the sculptures were
designed. Designed, period. Not designed by God or designed by aliens, but
designed, period. If you agree that we can tell in both cases that the
objects are designed, then we can drop both examples and move to the next
stage of the argument. But if you are saying that it is not a certainty
that the sculptures and space craft are designed, then say so, and say why.

You also wrote:

>Likewise the alien space probe. You know that a human space probe was
designed by an intelligent life form (a) [ a human life form]. If you
believe life arose naturally on earth, it is reasonable to assume that
it could arise naturally on another planet, and that therefore the
alien probe was designed by an alien life-form (b). You can even
estimate the probability of life arising on another planet.

"If you believe life arose naturally on earth" -- you're slipping in the
very premise that is the subject of debate! Everything that follows from
that premise is illegitimate for someone who *doesn't* believe that life
arose naturally on earth. If we are going to debate the Martian sculpture
example, or the spacecraft example, the question of the applicability of
such examples to the case of the first living cell on earth (or on some
other planet) must be kept open, and the *assumption* that life arose
naturally on earth and on other planets (if by "naturally" you mean
"undesigned") prejudices the whole inquiry.

I'll hold off replying to your other comments until I've heard back from you
on these.

Cameron.

----- Original Message -----
From: "Iain Strachan" <igd.strachan@gmail.com>
To: "Cameron Wybrow" <wybrowc@sympatico.ca>
Cc: "asa" <asa@calvin.edu>
Sent: Thursday, November 12, 2009 5:49 PM
Subject: Re: Of Martian Sculptures (was: Re: [asa] on science and
meta-science)

On Thu, Nov 12, 2009 at 8:49 PM, Cameron Wybrow <wybrowc@sympatico.ca>
wrote:
> David:

> But the same objections apply in the case of the travel-worn space probe.
> We
> have no independent knowledge -- knowledge other than the existence of the
> probe itself -- that any other intelligent life exists in the universe, so
> objection (a) above applies. And we have no independent knowledge --
> knowledge other than what can be inferred from the probe itself -- of the
> nature, habits, motivations, inclinations, etc. of the purported
> designers,
> so objection (b) applies.
>
> In the case of the space probe, our inferences, both of the existence and
> of
> the character of the purported designers, depend *entirely* upon what we
> can
> discover from the probe itself. We have no warrant for inferring anything
> else about the designers. Our certainty that such designers exist, that
> they have certain capacities, etc., springs from a *design inference* that
> *rests entirely upon the very thing whose design status is being debated*.
> So, when the question is asked: "Is this metallic object from outer space
> designed, or only the product of chance and natural laws?", our design
> inference is made in violation of objections (a) and (b) above. Yet we
> would feel certain that our design inference was valid, and rightly so.
> Our
> own practice would show that we do not consider the criteria used to
> reject
> design inferences (given above) to be sufficient criteria for such
> rejection.
>
> It follows that the TEs on this list should abandon the above-described
> *general* argument which rules out design inferences from natural objects
> to
> a designer of natural objects. There remain available to TEs, of course,
> *particular* objections that *particular* inferences from nature to a
> designer of nature are invalid, or are made on evidence that is too
> skimpy,
> and so on. I carry no brief against such *particular* objections. It is
> the general objection that I reject. In practice, the real-life behaviour
> of everyone on this list negates the objection, which shows that it is not
> a
> principled objection, but an intellectual *deus ex machina* called up to
> rid
> TEs of the hard work of having to deal with particular design inferences,
> one by one.
>

Sorry, but I'm not convinced. I think you do have independent
knowledge of the likely nature and inclinations of the designer of the
spacecraft. That independent knowledge is the existence of us; for we
design and build space-ships with much the same likely intent as the
designers of the alien space-ship - namely presumably for the
exploration of space.

Consider my building example. You say that you know about the
existence of the Architect (a) for Building A. Building B has similar
properties to building A (doors, rooms, windows etc), so you infer
that it also was designed by an Architect (b). You don't know _which_
Architect, but it is reasonable to assume that it was an Architect
with similar intentions to the designer of building A.

Likewise the alien space probe. You know that a human space probe was
designed by an intelligent life form (a) [ a human life form]. If you
believe life arose naturally on earth, it is reasonable to assume that
it could arise naturally on another planet, and that therefore the
alien probe was designed by an alien life-form (b). You can even
estimate the probability of life arising on another planet.

The problem with just postulating an unspecified "Designer" is that
you can't estimate the probability of the existence of such a thing.
With the alien space probe you can estimate the probability (even if
it is a rough thing like the Drake equation).

Fundamentally, my version of the "independent evidence" objection lies
in Bayesian statistics. One makes an inference based on a prior
probability (of existence of said designer), modified to a posterior
probability, based on the evidence (existence of the watch, statue,
space probe), to a posterior probability.

But any such calculation breaks down and is literally nonsensical if
you can't estimate a prior probability. You can't estimate a prior
probability of God existing in any realistic way. It comes down to
your philosophical belief. An atheist will simply make the prior
probability so low that the posterior is also incredibly low.

I had two colleagues that were arguing about the probability of God
existing. One said 10^(-100) and the other said zero. The 10^(-100)
fellow said of the zero fellow; "Now that's what I call faith!"

Iain

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Received on Thu Nov 12 19:31:04 2009